Bookatorium in Echo Generation is a wondrous place that offers all kinds of items crucial to in-game progress. However, it's also the workplace of a very unenthusiastic salesperson.
Echo Generation's Downtown location is full of interesting establishments. While there, you can visit Video Busters, Tea Tunes, the School, and the Bookatorium.
The Bookatorium offers a bunch of different magazines, comic books and more but you specifically need one book that's not for sale - it's part of the display. While the display is gorgeous and all, you need that book to continue the story and you'll have to resort to distracting the clerk and taking it for yourself.
How to distract the clerk
Go to the history section of the store and pick up the Heavy Encyclopedia that's just lying there. Next, drop the big book into the opening on the floor to jam the toy train.
After that's done, you can try directing the clerk's attention towards the problem but her manager isn't there so she won't do anything about it. You can fix this by going into the school (the side door is locked but you can climb in through the window) and calling the store from the principal's office.
Once you've entered the school through the window, leave the classroom and go into the hall. You'll find a vending machine with some health-restoring foods if you go right in the hall.
Going left will result in a mini heart attack due to the one and only jump scare in Echo Generation. The Prom Ghost will blink and scream when you walk past the Prom Night poster but you can avoid fighting it right then and there if you hug the opposite wall.
The principal's office is at the left end of the hall you're already in so there's no need to fight the ghost if you first want to get your heart rate down a bit. Trespass and look around to find some goodies and then use the phone to call the Bookatorium.
Bonus info: Defeating the Prom Ghost will reward you with one free book voucher you can exchange for a certain magazine.
Once you're done, climb back out of the window and go to the Bookatorium. There are three items you can swipe while the clerk is freaking out and trying to fix the train. She won't return to her post until all three items have been claimed so you don't have to worry about being fast.